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How does a taildragger steer (taxi) differently to tricycle gear?
I'm aware that there is a difference of some sort. Does a taildragger inherently require more room than a nose gear to taxi around a corner?

No, it really doesn't. As to how it physically steers, that is dependent on the aircraft, some use only differential braking and a caster tail wheel while some have steerable tail wheels. Either tail dragger or tricycle, usually the pivot point of the aircraft is the same, between the main gear, so the turning radius isn't really affected.

Only in the sense that your typical nose dragger can usually swing the tail over the various airport edge lights & the tail dragger usually can't.

It very much depends on the tail-dragger. Many vintage aircraft don't have wheel brakes at all and steer using the rudder, which has the tail wheel or skid attached to it. On these aircraft, steering is ineffective at low speeds, just like when steering a ship with a rudder. Unlike on a ship, you can increase your steerage by adding a burst of power and using the slipstream over the rudder to push it sideways. Very experienced pilots can turn almost on the spot at very low speeds this way, but in a tricky situation it's a judgement call whether to make a wider turn at low speed or add power and risk speeding up. For this reason it's good to have a little extra room, to make sure you can stop completely at any point and still have room to make the turn.
Dan Pichelman makes a good points in the comments. If you take a tricycle and a tail-dragger with the same turning circle, and look at the tyre marks on the ground, the tail-dragger's marks will be much bigger. That tail wheel right at the aftermost point traces out a huge circle, while the tricycle's wheels are very close together. For this reason, you need the whole turning circle to be free from obstacles such as edge markers and lights, while a tricycle can do a full turn with its tail overhanging any obstructions.
One more taxiing issue is visibility. Tail-draggers (again, especially earlier ones) are nose-high on the ground, and the engine cowling tends to prevent the pilot seeing straight forward. There have been many incidents of tail-draggers taxiing right onto smaller aircraft or obstructions straight ahead of them. (It used to be very common with Spitfires.) To avoid this, pilots are taught to weave as they taxi, so they can always check the ground ahead by looking either side of the nose. (Think of it like the clearing turns you make on a long climb.) While a tricycle might go straight along a taxiway it can only just fit into, a tail-dragger wants a much wider taxiway so that it can weave like this. You also need to plan how you're going to make the weave go into a turn when you reach a corner: if you got to the corner as you'd weaved right over to its inside, pointing towards the outside of the corner, you'd need much more room to make the turn.
For all these reasons, while it's entirely possible for a good pilot on a good day to make turns just as tight as a similar-sized tricycle aircraft, it's a good idea to allow a larger unobstructed space on straights and corners if you're expecting tail-draggers, especially students.


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Why does the V-Bat not counter-rotate?
V-Bat is a VTOL aircraft built by a company called Martin UAV.
It seems to have a single pusher propeller. But then why does it not counter-rotate to balance the rotation of the propeller?
Any clear images of the mechanism or report would be great.

From what I see there are moving blades downstream which are possibly used to control the aircraft and offset the torque of the rotor.

Right underneath the prop (highlighted in red) there is a set of control surfaces (highlighted in blue).

it's very reasonable that these get set to counteract the induced rotation of the prop in addition to being a discount vectored thrust mechanism.

A VTOL Predator designed as a drone version of this aircraft.  Excellent!

Looking at the video of it, the V-BAT appears to have a fixed pitch propeller for simplicity, directly driven by the a small 2-stroke drone engine.
Two issues with counter-rotating props:

You now have to have a gearbox for the propellers to drive two concentric propeller shafts in opposite directions. Quite a bit of added weight and complexity.  Which means you'll need a bigger engine to boot. And away you go on the weight/complexity design merry-go-round (added weight > more power needed > more fuel because of the thirstier engine > oops more power needed because of extra fuel > oops need to make the prop gearbox heavier > oops need more power > oops need more fuel... you get the idea).
Stacking two propellers close together is very inefficient, if the propellers are fixed pitch, because the downwind propeller has to work in its sister's wake all the time, with the flow conditions always changing. It'll have to be set at a different pitch, and even then it'll never make as much thrust as the one above it.  And you'll STILL have to use anti-torque vanes for precise control, so you're not really eliminating that mechanism.

So much easier, simpler, lighter, to use anti-torque vanes large enough to counter the torque of the single propeller, for a machine that's kind of quasi-disposable anyway.

Don't forget that contra-rotating rotors do have also some advantages like they are more compact (which might be a must-have in some design) and the vanes would be used basically only to control the aircraft instead of antitorque+control so they can be made more compact too.

Of course, but the weight and complexity of a gearbox and the need to use variable pitch negates most of that.  The anti-torque demands aren't that high with a prop that small anyway.

source: Stack Exchange

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text:
Is it safe for a huge all black helicopter to be flying BELOW 500 feet over my house, for an hour now, spraying pesticides all over the area
How dangerous is it for a huge all black helicopter to be flying below 500 feet over my house, for a half hour now, spraying pesticides all over the area and my farm animals. It is shaking the whole house and almost took the tops off the tall trees in back.

Welcome, Eileen. Location, please?

Rural Cass County NE

Could you please add a photo?

The helicopter is gone now, but if it comes back, I will get a picture of it. This is not the first time we have seen it doing this. I just got an e-mail early this morning from a online neighborhood group in this area asking about this copter. They said they have also seen it flying this low spraying over their homes.

That's likely mosquito control.

No, it is spraying the crops with pesticide, a local farmer told me when I asked. The problem is, it is also spraying livestock, people & homes. It is so low over homes, if anything at all went wrong with the copter, it would go down like a rock. It is just above the tops of our trees and our trees are not 500 feet tall.

Pink one would not be much safer

It's not the fact that the helicopter is all black, or any other color. The small crop duster planes that normally spray here are bright yellow and never fly that low. It is the fact that this helicopter is so large, it is huge, and that it is flying that low over homes. There is no room for error. There is no "gliding" it down if something would happen.

Well if it was spraying crops that's a problem if it's dumping pesticide all over the place.  Part of the reason helicopters are used is because extremely precise application is possible.  Aside from your own concerns of getting doused, the farmer is paying for product that is not going where it's supposed to go.  There's something more going on.

Can you please clarify the question?  Are you contending that the helicopter was within the (upwardly projected) boundaries of the walls of your house, below 500', for an hour/ half hour?  Continually, or intermittently?  Thanks.  And could you please edit the question so that body of question is consistent with the title, are we talking about a half-hour interval, or a full hour?

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Can I fly an RNAV DP (GPS & RNAV 1 required) with no FD/AP?
I’m currently planning an instrument flight which includes a full stop at an airport with a RNAV (Obstacle) Departure Procedure.
The procedure plate requires RNAV 1 and GPS.
In ground school I remember learning that a FD is required when flying a RNAV 1 approach. My airplane is a Cessna 172S that has WAAS but no AP/FD.
When looking up the FAA AC 90-100A it talks about the FD but also mentions a “lateral deviation indicator” which would be my pink needles when loading the DP in my G1000.
The full sentences reads as follows:

(2) Pilots must use a lateral deviation indicator (or equivalent navigation map display), flight director and/or autopilot in lateral navigation mode on RNAV 1 routes. The full-scale course deviation indicator (CDI) deflection value of ±1 NM is acceptable.

Can I now fly this RNAV DP with my WAAS C172S which is not equipped with an AP/FD or not?
It's a 2009 C172S G1000/G with PBN C2D2 but not equipped with any AP/FD. The approach plate in question is the ATASY2.ATASY Departure out of KTDO.

Click to view

The AC only mentions the part that I quoted regarding a lateral deviation indicator, flight director and/or autopilot in lateral navigation mode.

Please let me know precisely the equipment aboard your Cessna 172 and the departure plate in question

It's a 2009 C172S G1000/G with PBN C2D2 but not equipped with any AP/FD.
The approach plate in question is the ATASY2.ATASY Departure out of KTDO.

The answer is right there in your quote from the AC. Are you having trouble parsing the “and/or”?

As @StephenS indicates, my reading would be: you can use a lateral deviation indicator (CDI), or a flight director, or an autopilot in lateral mode, or any combination.

Thank you both! That definitely answers my question.


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Why does the B-29 bomber not have propeller control lever in Cockpit/Engineer station
The aircraft of WWII usually had a propeller control lever. But I didn't see the propeller control levers in the flight engineer station.

Related: https://digitalcollections.museumofflight.org/items/show/49678 -- see p.29 in the manual (p.36 in the on-line presentation) -- directions for feathering say that the pilot will push the feathering button -- earlier in the text we find this interesting comment -- "2. Freelance exptrimentation in the B-29 type airplane is hazardous and wasteful. This experimentation must stop."  Fascinating --

As the old saying goes, “regulations are written in blood”. You realize, of course that that was included in the flight manual because, at some point or other, some schmuck decided to play test pilot with a B-29 by experimenting with the prop feathering controls, got out of control and drilled the hole halfway to China.

On the B-29, the feathering switches and manual propeller pitch control switches (marked as "propeller increase and decrease RPM switches" in the diagram) were on the center console in the forward cockpit.

Source: B29 Flight Manual

This shows that there are switches are, but does not really answer the question - why there's no lever?


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Why is there no Maltese Cross in this non-precision approach chart which has a FAF?

I am wondering why this chart does not show the FAF with a maltese cross as it is used in non-precision approaches to depict FAF.
The chart’s briefing strip refers to D6.0 as the FAF and on the plan view FD23 code can be seen(which also indicates that this the FAF).

It could be a charting issue.  It is also the same for the NDB Z Rwy 23 approach into LTAY.    Feel free to ask Jeppesen and they will tell you if the chart is in error.
https://support.jeppesen.com/


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Does a Antonov An-225 have a Turn and Bank Indicator?
May I know if there are any turn and bank indicators on the pilots instrument panel and where is it located at?

Related: What was the flying instrument panel layout type behind the yoke onboard the Antonov 225?

As has been pointed out in other posts, the top right instrument, appears to be a VSI (white needle) with an overlaid bank indicator (gold dial) over a ball slip/skid indicator.

That's not a VSI, the scale is wrong and it doesn't have a negative indication for descent. I have a Cuban friend who trained in Russia, I will ask him what it is.

It goes 10-20-30 clockwise, and 10-20-30 counter-clockwise, as a VSI would.  You posted the picture!  ;)  See also https://i.sstatic.net/liZTS.png

Turns out you nailed it. Combo VSI with an appropriate range for the behemoth's performance, with turn and bank. My friend Guajirovich confirmed it.

And sadly, these questions and comments are all worded present tense.  The An-225 had a turn and bank.  :(

Nah. Has. The second one is going to be finished. https://www.cnn.com/travel/article/antonov-an-225-kiev-ukraine/index.html

@UshbyTechnicalTeam presumably the device has both a canted bank gyro AND a connection to to the static ports inside the same enclosure.  Your intuition is correct, there’d be no way to accomplish both objectives with just one mechanism.

There is no reason an instrument cannot have both a gyro and a static air pressure mechanism.

@Ushby, this is a combined gyro+air (btw, static pressure, not dynamic) instrument. This one.

Yes, it does. Top right instrument is a combination VSI and turn and bank.

From my point of view it makes sense to have a combined instrument. When you are trying to make a coordinated turn often you want to maintain your altitude, or maintain a stable sink or climb rate. It makes sense to me to have that information centralized in one instrument. The part immediately above the center of the instrument is the bank indicator. As far as I know, the POH for the AN-225 is not publicly available. At least I have not been able to find it.

@Juan, at least An-124 POH is available (but in Russian as scanned pages), and it has an almost identical panel. Yes, this is a combined VSI and turn-and-bank indicator. It is designated ДА-30 (example).


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Hovering for free
I'm thinking about light solar drones, and started wondering if you could hover while not using any power by flying downwind. Something similar to how prey birds hover while tracking the ground. It seems they can just keep their altitude without using energy, at least in strong headwind. Could this be a feasible way to "rest" the drone while charging the solar panels instead of having to land?

Re "Something similar to how prey birds hover while tracking the ground. It seems they can just keep their altitude without using energy, at least in strong headwind. " -- not till well into the early 20th century did humans really start to understand how birds of prey soar without flapping their wings.  Even Otto Lilienthal, who personally experienced soaring flight (in ridge lift) in foot-launched weight-shift gliders of his own design, had some whacky ideas about how a bird manages to rise while circling over flat ground, without flapping its wings.

... wondering if you could hover while not using any power by flying downwind.

If you're anchored to the ground like a kite, then yes. Otherwise not of course, the relevant airspeed for a flying object or animal is the surrounding air, not the ground speed. When flying, upwind is wherever the nose is pointing.
Those beautiful birds of prey hanging still in the air are catching updrafts, like gliders do as well which seek them out - caused by winds being deflected upwards by dunes for instance, or by differently coloured surface areas which heat up the local air more, causing it to rise faster.
So for more info on where to "rest" the drone while charging, best talk to the local glider club.

"upwind is wherever the nose is pointing", plus sideslip angle

If I wanted an aircraft good at soaring, rotorcraft is not where I'd go.  Least of all ones with fixed pitch rotors with no collective.

@Harper-ReinstateMonica A classic kite shape is not very aerodynamic, yet it stays up.

For a small drone, the local glider club won't have any useful information I suspect. We fly a couple hundred meters between spots where we hope to find updrafts. Sometimes we do, sometimes we don't but I don't think it would be feasible for a drone to fly that far.

When you said "Otherwise not of course" are you claiming that you can't hover above a spot on the ground (0 kts of ground speed) unless you're tethered to the ground or have an updraft?

@Wyck In order to maintain altitude in unpowered aerodynamic flight, yes. The only other ways to maintain zero speed relative to ground while aloft and maintaining altitude are powered flight or geostationary orbit (the latter of which is only possible directly above the equator and requires a bit more than the budget of most hobbyists, to put it mildly.)

Does a bird wing not produce lift when air flows across it from front to back?  If it does, then a sufficient headwind would allow the bird to hover without an updraft.

@nasch A sufficient headwind would blow the bird backwards, unless it starts to propel itself by flapping its wings. There needs to be an equilibrium of horizontal aerodynamic force.

What if the wings are pitched downward as though in a dive?

@nasch Then the bird will be propelled backwards as well, it’s slightly worse because the wing produces less lift while there still is an inflow of air. Which will stop completely when the bird is just blown backwards like a leaf - until it starts flapping.

@Koyovis You obviously haven't seen me try to fly a kite!

@Harper-ReinstateMonica the OP does not talk about rotorcrafts, and there are fixed-wing drones like these: https://actu.epfl.ch/news/a-drone-that-flies-almost-like-a-bird/

@reirab You can also maintain zero speed relative to ground using buoyancy, i.e. a hot air balloon or airship.

@nasch Yes, that would work. We call that flight mode "gliding" and we do use it on airplanes as well (both specially designed gliders and regular powered planes with engine problems). In that flight mode the headwind can certainly keep the bird's position fixed relative to the ground. The energy needed to fight the headwind from blowing the bird backwards comes from the bird losing altitude (basically gravity). So you cannot really get away from losing altitude without any updraft

@Harper-ReinstateMonica Some of the first aircraft to be called "drones" (the original drones and where the word "drone" as being applied to aircraft comes from) are military target drones from between WW1 and WW2 and they look like this: https://en.wikipedia.org/wiki/Radioplane_OQ-2

@Koyovis On an aviation forum you might want to be more specific.  What does "not very aerodynamic" mean? In informal usage that usually means having low drag, but in the context of your comment that doesn't seem to make much sense.

You can 'hover for free' in a helicopter, but it requires the air surrounding the helicopter to be moving upwards, at the same rate that the helicopter is descending in 'autorotation'.  Being in autorotation requires no engine power, and if the air surrounding the helicopter is moving upwards as fast as the helicopter is moving downwards - then technically the helicopter is not moving, and could be considered as 'hovering for free'.
I have experienced this twice during my helicopter flying career:
Firstly within a thunderstorm.  There are horrendous updraghts and downdraughts within cumulonimbus clouds.  I once flew a helicopter into one of these, where at times I was still climbing whilst in full autorotation using no engine power.  Technically 'hovering for free'.  However, this was shortly followed be a period of still descending whilst at maximum engine power!  This is uncomfortable, not recommended, and I do not want to do this again.
Secondly, I have experienced hovering next to a mountainside, also whilst in full autorotation.  This was near to the top of a mountain ridgeline, with very strong winds blowing up the side of the mountain, whilst rescuing a fallen climber.  Again, the strength of the wind resulted in sufficient air blowing up through the rotors, that the result was the helicopter was in full autorotation, with no engine power.  But again, this was uncomfortable, turbulent, not recommended, and I do not want to do this again.

Let's not conflate "drone" with "rotorcraft".

Welcome to aviation.stackexchange. Thank you for sharing your experience on things you do not want to do again. I can imagine the thunderstorm experience necessitated a fresh set of underwear!

Technical question: Woun't such an upwind situation cause an increase of rotor speed (that you would compensate by adjusting the pitch of the blades which would in turn increase the the lift)?

This is the original drone and it certainly has wings: https://en.wikipedia.org/wiki/Radioplane_OQ-2

As Koyovis' answer correctly states, finding updrafts (especially thermally generated ones or ones generated by orographic lift) is the only way you'll get an ability to remain in the air without expending energy unless you're tethered to something holding you in a spot relative to the ground. Of course, you can also remain aloft more or less indefinitely if you go into orbit, but good luck getting there.
As for using solar power, landing to charge is going to be your best bet anyway because the most efficient way to have a solar-powered drone - by far - is to have your entire solar power collection setup mounted on the ground and just use that to charge a battery on your drone. Solar power is not anywhere near the energy density that many people seem to assume it is. Using solar power for flight is only even remotely feasible if the vehicle is rather large, but also quite light and not trying to achieve high speeds because it needs a very large area to mount enough photovoltaic cells to get enough power. Solar power received at Earth is only about 1,000 Watts per square meter (about 1,000 Watts per 10 square feet.) However, that's only near noon at a latitude where the sun is directly overhead and with no clouds obstructing the sunlight.
For example, the Solar Impulse 2 managed to circumnavigate the world (with lots of stops) using solar power. However, the thing had a wingspan larger than a Boeing 747-8 and a total wing area of 270 m^2 (2,900 sqft,) but weighed only 5,100 pounds, being able to carry only one person with the remainder of the weight being batteries, solar panel cells, its electric motors, and its very weak structure for its size (designed to keep structural weight to an absolute minimum value without falling apart.) It took off at 19.5 knots (22.4 mph, 36 km/h) and it cruised at only 49 knots (56 mph, 90 km/h) in the daytime and a third less than that at night to save power. On its circumnavigation trip, it began on March 9, 2015 in Dubai and returned to Dubai on July 26, spending 23 days, 6 hours airborne and the rest of that time on the ground resting and waiting for favorable weather to continue. (Weather constraints are much tighter when your aircraft only flies 49 knots and its structure is designed to be just barely strong enough to not disintegrate in good-to-moderate weather.)
Aside from a few special-purpose use cases (for example, research or surveillance aircraft loitering at high altitudes at low or mid latitudes for extended durations,) on-board solar isn't really a feasible power source for flight, least of all for rotary-wing aircraft, which are far less energy efficient than fixed-wing ones.

If you have an airplane floating above a conveyer belt while the air is stationary, relativity tells us that that is equivalent to an airplane floating in moving air above stationary ground. In the first case, the conveyer belt clearly doesn't help the airplane stay afloat, so the fact that, in the second case, the air and airplane are moving at a different velocity than the ground also doesn't help the airplane stay afloat.
A vehicle can't get energy, relative to some homogenous medium, by interacting just with the medium (it can gain kinetic energy by either spending potential energy or fuel, but it can't gain net energy). There has to be some gradient for it to gain energy. A vehicle can gain energy relative to the ground by interacting with the air (that is, if it starts at rest with respect to the ground, and is pushed by the air, its energy relative to the ground can increase) if the air is moving relative to the ground, but to get energy relative to the air, it has to interact with some other medium such as the ground (a solar powered vehicle is interacting with sunlight, which for purposes of this answer is a "medium"). A vehicle can gain energy relative to both by interacting with both (for instance, a sail boat interacts with the wind through its sails, and with the water through its keel).

@reirab My answer was in response to a question about unpowered flight, although I should have made that more clear. I've clarified that this is about net energy. Using up fuel to gain kinetic energy isn't gaining net energy (and neither is trading altitude for air speed).

Ah, gotcha. Thanks for the clarification. That makes much more sense.


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Garmin G1000 'Waves in a Circle' Symbol?
we had this symbol come up on a G1000 and could not find a reference for what it indicates. Could anyone tell me what it means?

It's a county flood warning:

COUNTY WARNINGS
County data (Figure 6-38) provides specific public awareness and protection weather warnings from the National Weather Service (NWS). This can include information on tornadoes, severe thunderstorms, and flood conditions.
Displaying County Warning information:
1) Select the Weather Data Link (XM) Page.
2) Press the MORE WX Softkey.
3) Press the COUNTY Softkey.
To display the County Warnings legend (Figure 6-39), press the LEGEND Softkey when County Warnings are selected to be displayed.

G1000 Pilot's Guide for Cessna Nav III p. 304 (the symbology is the same in all G1000 variants with XM weather and the legend can probably also be found in the Pilot's Guide for your variant if not a Cessna Nav III).

In other words @Justin, it means you are flying over water where you never expected it, so you may want to divert around in case of an engine failure.


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Density altitude difference (formula and Asa CX-3)
I am trying to figure out Density Altitude problem from the book and I get one answer by hand and another with CX-3 and cannot find the bug.
So problem goes like this,

Indicated Altitude    5250 feet
Baro  1010 hPa
OAT     27 C

I calculate,

Pa = ( ( 1013-1010 ) * 30 ) + 5250 = 90 + 5250 = 5340
Temperature = 15 - (2 * 5340 / 1000 ) = 4.32
Density Altitude in Feet = Pressure Altitude in Feet + (120 x (OAT°C –
ISA Temperature °C))
DA = 5340 + ( 120 * ( 27 - 4.32))
 5340 + ( 120 * 22.68 )

 5340 + 2721.6

 8061.6

At the same time my CX-3 calculator shows,

IAlt 5250 FT
Baro 1010 MB
PAlt 5339
OAT 27
DAlt 7890

Answer in the book says exactly that number.... but how did they calculate it, what I am doing wrong here?
Thank you all for helping out!

Bottom line is the formula (Density Altitude in Feet = Pressure Altitude in Feet + (120 x (OAT°C – ISA Temperature °C))) is an approximation to be used "in a pinch." Differences of about 200 feet (~2%) are fine, especially considering humidity differences may also effect density altitude by hundreds of feet. See the Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25B, beginning on page 4-4, for more information and web sites.
P.S. you might want to check the pressure lapse rate in your Pa equation.


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Desired track for aircraft navigation
I am working on a flight planning application and I am need to calculate the desired track(DTK) of the current leg and upcoming legs of a entered flight plan. The formula and logic of solving that is easy in code but what I am unsure of is when/where do I introduce magnetic variation when displaying this data.
It could be calculated at "Waypoint1"(start of leg) but then then over large distances as the magvar changes I'd assume this number would become inaccurate.
I could use the halfway point between "Waypoint1" and "Waypoint2" but then again over large distances this number could prove to be incorrect and provide the pilot with a inaccurate DTK on entry of the leg.
Using a WMM model we I can predict the magvar at any point with known lat/longs and I also have access to a magnetometer data output.
Does anyone know what RTCA or AIRNC manual that may point me in the right direction or have some insight on best practices?

Why are you specifying track as a magnetic direction? Shouldn't you calculate track in true?

That is a option for the user to select if the representation is in true, magnetic or user defined.

Is that something pilots actually need? What would be the use of "custom"? I also think you are assuming that the magnetic direction of a track is the same at the start as at the end.

The use case for the pilot is unknown but we have it as more as debug option for us here while we are developing. Can you elaborate on what you mean by the mag direction from start to end? Is that because the the magnetic variation changes as you traverse the globe?

Yes. Also, are your tracks great circles? Or are you assuming each track segment has a constant true direction along its length?

The references are RTCA DO-283 Minimum Operational Performance Standards for Required Navigation Performance for Area Navigation, and ARINC 702A Advanced Flight Management Computer System.
Within the FMS flight plan, the leg definition includes 'course out' for the starting fix and 'course in' for the ending fix. MagVar was applied using the MagVar for the fix.
Along the leg, DTK is established at the point along the track associated with the aircraft's current along-track position. It's the point on the track where a line normal to the DTK passes through the aircraft (the length of this line is the cross-track deviation.) DTK at any point on the leg is the course of a tangent line at that point. Current DTK uses the MagVar at the current along-track position.

Thank you. I will have a look for these documents.


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Will getting a 4-year degree actually make a difference?
I'm currently working on my PPL, still in high school. I should get my PPL almost exactly on my 17th birthday. Instrument comes after, then complex, etc, etc. Should I still consider a college or go right into time building jobs after I graduate? I could instruct for a year or so until I have the hours to apply at a Part 135 operation. Then its all hours until I'm 23 and eligible for my ATP. At a mainline carrier, will they actually consider me if I don't go the 4 year degree path? Part of me is a little uneasy about spending 4 years and 100K+ on a degree I'm not really interested in and won't ever use.
I could also do an online degree while flying for a 135 or flight school.
Any advice?

A four year degree will help when you are inevitably furloughed.

Regarding $100K+ for a degree, I'll assume you're in the US.  Consider looking for reputable state-subsidized options, including possibly community colleges with a transfer to a more reputable school to finish the degree.  You can also save a lot on living expenses if you're able/willing to stay with your parents and commute to school.  Ultimately you just need to be able to say you have a degree to check various boxes on automated filters, so look for the most cost effective option that still checks those boxes.

@MichaelHall In that case, why not start the degree when furloughed?

@RodrigodeAzevedo Because you’ll be unemployed and have bills to pay.  A full-time college student can live in a  dorm on student loans if needed; a furloughed pilot (who can be recalled at any time) with a house and family cannot.

If you don't get a degree, what happens if between now and when you are 23, for some reason, you can no longer fly (a sight related illness for example).  If you are already 2 years into a 4 year degree, you still come out with a degree that may be useful elsewhere.

Airlines in North America are starting to waive degree requirements but they will compensate for that by demanding much higher flying experience, or at least graduation from one of the aviation colleges.
The degree demonstrates intelligence and a the ability to absorb massive amounts of information in a hurry, which is what will happen when you take a jet type course (known as "drinking from a firehose").
As far as your own career path goes, if you go into flying and work up the ladder with only a high school education, and you "medical out" at 30 years old (it happens), you are back to square one, switching careers with no education other than your flying experience, which is useful to absolutely nobody.
If the opportunity is available to finish high school, get all your ratings, AND go on to university to get a STEM degree, you would be insane not to take advantage of it.  Don't let the impatience of youth get in the way of maximizing your career potential.  As you get older, time will fly past faster and faster, and you will regret not taking the time off for the advanced education.
Meanwhile, get an instructor rating and instruct part time as you complete your education.

Aside from the medical risk, there's the risk of a downturn and layoffs. Get laid off in your 40s and be forced to change employers, you could lose 10-15 years seniority and have to start over at entry-level wages. Hard to do if you're married with kids at that point. Have a backup career plan. A marketable degree is just good sense.

@Gerry I don't disagree that having a backup plan which includes a STEM degree is a good idea, but realistically falling back on a qualification you earned 10+ years ago in a field you've never practiced in is unlikely to get you a non-entry-level job. At that point whatever fraction you remember is going to be out-of-date, and potential employers can see that.

Not much to add except consider aviation related degree, like focusing on aerodynamics or similar. That will also open other opportunities in the field.

@brhans While that's true, entry level for engineers is better than a lot of options including many flying jobs. As an engineering manager I personally hired two ex-pilots in their 40s who not interested in continuing as pilots. They were both very good and came up to speed quickly. While some STEM jobs require specialized and current skills, many don't. You may have to learn new tools, but the physics hasn't changed. I also know a number of pilots that have side gigs that help keep their skills up.

There's also opportunities like flying for a manufacturer in production or possibly even experimental test, if you have the right credentials and several thousand hours of jet time.  Production test is a fraction of the hours of a line pilot, but way more interesting and fun, and you're home most nights.  It's hard to have a life when you spend half the month in hotel rooms.

I will preface this by saying that I am a university educator. When I was at the Singapore Air Show in 2014 (I think it was), I spoke to the HR manager for Singapore Airlines, and he said their requirement was not only a 4-year degree, but one from a top 200 ranked university on the QS ranking scale. I will add that I do not think this was enforced, because I did eventually have graduates from our 3-year degree and top 300 university that became pilots for them.
What Qantas and others would regularly say to us (every year I would have CEOs from airlines and airports come in and talk to the graduating class as part of their final year thesis class) was that a degree showed a commitment and ability to learn. Given being a pilot is a lifelong learning process (you are forever going to be doing new training and being tested and checked), a degree suggests you have no issues with this, and you were a good investment.
From what I have seen, if you can build a career by just flying, that is a good idea. I think the future pilot shortage is going to make it likely that a degree or not is an insignificant dimension for companies to look at. This is likely a time where you could easily just fly and then once with an airline, if a promotion etc requires a degree, you can get one part time.
I would encourage you to reach out to your dream companies HR department. You will find they are happy to hear from you, and willing to provide advice. When I was in year twelve, I got a graduate recruitment pack (for uni students) from BAe Systems and DERA (the former DSTL+QinetiQ). Their response is the most important. In fact, I would reach out to them on LinkedIn.

A more blunt way to put it is, a degree is a substitute for an IQ test, companies not being able to do that any more, and also demonstrates ability to absorb vast volumes of information rapidly, which is what will happen on a type course. The degree category is irrelevant, as long as it's not in a soft topic like humanities.

@JohnK, excellent comment, but I don’t totally agree with the last sentence.  An engineering degree will help you understand more detail about the inner workings of the aircraft systems, but a big part of the job, (most jobs really) is dealing with people.  Crew, dispatch, ATC, pax…. A little “soft topic” college psych, comm, and soc are a must in my opinion for success in any meaningful career.  (Maybe prereqs already for Engineering?)

I've known capts who were on selection boards and they used to tell me the degree category isn't that important.  It's just a marker that shows you can handle vast amounts of information.  Once you're flying, your world narrows down to the knowledge required to do the job and the knowledge beyond that my come in handy is some circumstance, but it's not critical during selection.

Regarding the "future pilot shortage", keep in mind that there are companies working on self-flying aircraft. While that's not for tomorrow or several years down the road, given the exponential growth of technology you do need a backup plan. You don't have to do the 4 year degree in 4 years. You could do it part time over the course of 6 or 8, and have learned solid analytical skills and have something marketable. Mechanical / Aero engineering, or business/marketing if math/calculus is too hard.


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Is it okay to do power off stalls in the clean configuration for a check ride?
I’ve been renting a plane for a while and the owner has asked due to a safety concern that we don’t use flaps in our stalls or slow flight.
The airplane flying handbook and the ACS call for these to be done in the landing configuration. Would a DPE be okay with doing these maneuvers in a clean configuration given that is how we have been asked to fly the plane?

The owner might be saying "do not move them during stalls or slow flight" for the same reason they are not moved near the ground:  one might move and one does not, creating a serious aerodynamic imbalance.  One might ask for a clarification, and bring your instructor with you.  Flaps can be set before any of these manuevers.

I always do stalls when flying a new type. At sufficient altitude, of course. Not doing them robs you of the experience when you might come in slow to a landing and an unfortunate gust brings you below stall speed. Even with the usual precautions like flying the approach 10 knots above the usual speed in gusty weather cannot rule out such an event completely.
Doing them only in the clean configuration is not enough. The stall characteristics might differ a lot between the clean and landing configurations. But doing them clean as well is sensible.

That would ring alarm bells with me, and I would get to the bottom of it before I fly that airplane again. Is there a maintenance issue? Something the owner hasn't fixed? If it's because the owner is worried about accidents, it's practicing the recognition of approach to stalls and stall recovery that prevents accidents.

Many readers will be curious to know, what safety issue could have led to this request?  Seems odd.

From the ACS for power-off stalls:

PA.VII.B.S3 Configure the airplane in the approach or landing configuration, as specified by the evaluator, and maintain coordinated flight throughout the maneuver.

Unless you are in an aircraft that uses zero flaps in the approach configuration, then a power-off stall requires flaps per the ACS. This doesn't preclude practicing power-off stalls without flaps, but that's not a maneuver you'll be tested on.
I suggest you clarify with the aircraft owner. It doesn't make sense not to do slow flight and stalls in the approach and landing configuration. It's much safer to experience the slow flight edge of the envelope at safe altitude than to only be exposed to it when close to the ground!


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What does a medical certificate look like?
I can't find any images of a medical certificate other than the old version that was combined with the student pilot certificate. What do new medical certificates look like?


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Is there a "learner's permit" for pilots?
To get a driver's license (in Oregon), you have to pass a written test, get an instruction permit, get 100 hours of supervised driving practice, take a drive test, then get your driver's license, at which point you can drive alone.
I know pilots have to get a certain number of supervised flying hours, and can then get a pilot's license and fly alone. Is there an equivalent of the instruction permit, or can you just start flying as long as there's a licensed pilot who can take over?

Someone will be along with a more comprehensive answer I'm sure, but here's one tidbit to get you going: flying solo is not only allowed before going up for your full pilot's license test, it is a requirement!

@randomhead oh, that's interesting; what's the point of that? Since nobody's in the plane to make sure you fly well, how does it determine anything other than "you can fly alone without crashing"? Surely that's determined before someone can fly solo?

I suggest starting here: How to become a pilot.  After reviewing that, you can come back here with more specific questions.

@Gerry thank you! So it looks like the process is basically get a medical exam, take flying lessons, get a student pilot certificate which is analogous to a learner's permit, take more flying lessons, fly solo, pass a "practical test" analogous to the drive test, then get a pilot's license?

Don't forget 'ground school' where you learn theory, weather, rules of the air, navigation, etc. Then you can take the 'Written exam' (it's actually computerized.) It generally helps if you get started on this before you start actual flying. It also helps to have some dollars saved in the bank. Once you start flying, it helps to fly regularly (weekly). If you drag it out you lose retention and have go over stuff again and that just means more flying and more hours and more money. Despite what the rules say, most students take about 50-60 hours to get their certificate.

@someone, your last comment is the perfect answer!

You can start flying and logging the training time received from a certified flight instructor without meeting any other practical requirements. If the flight time will not be logged, there is no regulation that prevents you from flying an airplane as long as there is a pilot on board. (There are of course implicit requirements here such as this pilot be acting as the pilot in command and can't just literally "be on board", drunk in the back seat, without a valid medical certificate, in a plane for which they are not rated, etc.)
In your example above, the parallel to the instruction permit in aviation is the student pilot certificate. The student pilot certificate, along with a medical certificate, (and relevant endorsements from your flight instructor) are required only when you fly solo.
While you can (and will, should you pursue your license) read about the various requirements in the CFRs for example 14 CFR 61.51(h), the following FAA page Become a Pilot is a more accessible reference that may answer some common related questions.


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Why is it fairly common for the same aircraft to declare two emergencies, usually radio failures, in less than an hour?
I get notifications from FlightRadar24 whenever a plane squawks 7600 or 7700. It happens a lot; I've received eight today. (It seems like more happen on weekends than on weekdays, probably because more GA pilots can fly on weekends.) The last two, however, are the same helicopter squawking 7600, about 40 minutes apart. This happens every few days, usually with 7600 but sometimes 7700. Normally it's an airplane, not a helicopter, but I don't think this is the first helicopter that's done it; I probably just see more airplanes because there are more planes in the air than helicopters, so it would be expected that most emergencies woutbe declared by planes.
Why do repeated emergencies like this happen? Does it mean that the radio failed, the pilot landed and thought (s)he had fixed it, then took off again, and the radio failed again?

Can you give some example days/times and tail numbers?

Please remember that websites such as FR24 are for hobby use. The data they provide is not necessarily accurate.

@tedder42 the most recent was N111MF, a Robinson R44 helicopter, and the notifications came through at 04:50 and 05:29 UTC, January 29.

There's going to be a little speculation here, but I believe this may be a Flightradar24 thing (or a ground radar thing), and not an aircraft thing.  Helos tend to stay very low, and radar isn't always the best at low altitudes.
A decent example of this is in North Carolina over the Pamlico Sound.  I've flown sevral flights on VFR flight following (VFR FF henceforth) into and out of KFFA (First Flight), KMQI (Dare County), KHSE (Hatteras/Mitchell) and W95 (Ocracoke).  FFA and MQI are on the boundary of  the Norfolk (ORF) and Cherry Point (NKT) TRACON (Approach control) sectors.  ORF can see you down to about pattern altitude at FFA and MQI, but NKT can't.  Flying into and out of HSE and W95, NKT TRACON can't see you at all (you'll fall off radar at about 2500-3000), so we actually have to make special reports if we're flying something like the RNAV (GPS) 7 approach at HSE.  That entire approach is flown below radar from the IAF at CULAT until landing at HSE, so if we get off on our speed or profile, we have to tell NKT.  That's also why the go around is a climbing left turn all the way to 6000 when the minimum safe altitude is 2100 - at 6000 we're guaranteed not only obstacle clearance, but radar coverage.
Long story short, that was a very verbose way of saying I think this is an artifact of radar and ground tech rather than something on the aircraft.  But take this with a grain of salt, none of us actually know what was happening in that aircraft, so this is all still speculation.

So you're thinking the plane goes out of range of the receiver then comes back in range, causing the notification to appear twice?

@Someone That's precicely what I think is happening.  It seems weird that this would happen in Dallas (I looked up the helo in question), but at the same time, helos tend to stay within about 1000' of the ground, which can easily be low enough to drop off radar.


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Do other countries have the no-cell-phones-on-planes rule?
The answers to this question list mobile apps that presumably need Internet and are intended for use on small planes. I assume Cessnas and similar planes don't have satellite internet; how do these apps connect? They appear to be mostly used in Europe; do other countries besides the US allow cell phone use on planes?

To answer the question how do these apps connect?

I assume Cessnas and similar planes don't have satellite internet;

correct, at least not any of the Pipers/Cessnas I've flown but Cessna does make some stuff much larger than a 172 these days...

that presumably need Internet

This is incorrect, in the US and many other countries now where ADSB-Out is required for aircraft mobile apps can plot traffic as long as they connect to an ADSB-In unit. In the Piper I fly there are 2, the Garmin 650 Nav/Comm and a Sentry, both of which I can connect to my IPad and have it display traffic.
I personally use ForeFlight as my electronic flight bag, but there are others like Garmin Pilot all of which have off-line caching of charts/nav-data/information so that you don't need a connection to render anything. Pre-Loading required charts of an area is part of my preflight. ForeFlight offers both internet and ADSB traffic.
Also of note, while I wouldn't rely on it and it could be an issue to actually use your phone in flight, plenty of GA ops occur low enough to simply receive cell service.

"I assume Cessnas and similar planes don't have satellite internet"
It's not an issue for small single-engine planes anymore. You can get handheld satellite Wi-Fi hotspots (e.g. Iridium GO!) which work when placed on a glareshield or with a suction-cup windshield antenna.


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Under what conditions do airplanes stall?
I've seen somewhat conflicting information on when planes stall. I've seen references to "stall speed," apparently a speed below which the airplane will stall, but stalling also seems to be caused by the angle of attack. The tag wiki for stall says:

A stall is an aerodynamic condition wherein the angle of attack of a wing increases beyond the "critical angle of attack", causing the wing to cease generating lift. It's important to note that stalls can happen at any airspeed and in any attitude; the only cause of a stall is exceeding the critical angle of attack.

Under what circumstances do airplanes stall? How are stall speed and critical angle of attack related? Is stall speed the airspeed at which the critical angle of attack goes below 0°, causing a stall in level flight? Or is stall speed even a real thing?

Comments are not for extended discussion; this conversation has been moved to chat.

Stall at subsonic speeds depends ONLY on the AoA; you can (for real) fly an aircraft at half it's stall speed without having it stalled. For that, you will have to fly in NOT MORE THAN a quarter-G flight (since you now have 1/4th the dynamic pressure). So long as the critical AoA has not been exceeded, the aircraft will not stall.
But turns out, planes must fly in a 1G flight most of the time. And if all other values are held constant (mass, configuration, CG position etc.), with engines producing minimum/negligible thrust, in a 1G flight, then the speed (IAS) at which this critical AoA will be achieved can be determined and consistently reproduced. This is the stall speed, and an aircraft physically cannot fly below this speed - in a 1G flight.
In the lift equation, hold the following three variables constant: lift, because in 1G flight, we need a constant lift for a constant weight. Lift coefficient, hold it at its maximum value (Cl-max), since this is the point beyond which stall occurs. And surface area, since we're only using one particular aerofoil. With these three constant values put in, the remaining variable - dynamic pressure, is determined; there is only one value for dynamic pressure (IAS) which now fits in this equation. This IAS is the stall speed. If an aircraft, originally flying at this speed slows down any further, the pilot will instinctively pull back on the control column to obtain a higher Cl, which they need in order for the aforementioned constant lift to be maintained. Unfortunately, the Cl is already at its maximum value, and pitching up further will only reduce the Cl, since the aircraft will have stalled.
The aircraft will physically not be able to support a 1G flight below this speed - the 1G stall speed, but that does not mean that the aircraft also cannot support a less than 1G flight.

Comments are not for extended discussion; this conversation has been moved to chat.

Stall is defined as the point where the lift curve slope over angle of attack becomes flat or the lift coefficient peaks. It is caused by progressive flow separation on the suction side and happens generally when the airplane is too slow to create the desired lift. In a tight turn this happens at a higher speed than in level flight, and in a parabola flight the airplane will never slow down enough to stall.
In rare circumstances you also can stall an airplane by flying too fast.
The stall angle of attack is not constant but varies with speed, altitude, Mach number and the rate of angle of attack increase, as discussed here and here. Since the lift curve slope of a wing does not change with the pitch rate, a high pitch rate will indeed increase the stall AoA by up to 50%.
Speed and altitude effects are expressed in the Reynolds number, and this will also shift the AoA up by several degrees when increased from, say,  200,000 to 5,000,000. The influence of the Mach number will really manifest itself above Mach 0.5, but if the leading edge radius is small, it can already make a difference of several degrees between incompressible conditions and Mach 0.3. Stall at higher Mach numbers is more complex, because before lift drops, the wing will experience increasing buffeting, which by itself will limit the operational AoA.
Next, pitch angle and angle of attack are not the same, but they differ by the flight path angle and the wind angle of attack, which is nonzero if you fly in an up- or downdraft. This is discussed in detail here.
If your engine or airspeed allows, you can fly a full loop without ever stalling the airplane.

Stall is a complex phenomenon that happen when the airflow on the upper surface of a wing cannot follow the wing's curvature anymore. At that point there is a:

drop in lift;
rise in drag;
and a bigger nose-down tendency.

This picture (source) nicely depicts this detachment of the airflow:

Stall depends (almost) only on the angle of attack of the wing. The easiest way to visualize it is by looking at the plot of lift coefficient $C_l$, which has typically a trend like the one underlined in blue here under:

The top of that curve is the maximum lift coefficient $C_{l_{max}}$ which can be extracted from that wing before its stalling; in this case $C_{l_{max}}$ is some 1.6 reached at a AoA of some 16°. Beyond that value the wing stalls as signalised by the sudden drop of $C_l$. Note how $C_{l_{max}}$ depends on Reynolds number $R$ and surface finishing (roughness).
By definition, lift is calculated as:
$L=½ \rho V² S C_l$
where $\rho$ is air density, $S$ wing surface and $C_l$ the lift coefficient as just seen.
Now, being $C_{l_{max}}$ known, from this lift equation we can simply calculate the speed $V$ at which the wing stall:
$V_{stall}=\sqrt{ \frac{L}{½\rho S C_{l_{max}} } }$
For obvious safety reasons $V_{stall}$ should be as low as possible i.e. the denominator as high a possible. This can be achieved using a bigger wing surface $S$ and/or increasing $C_{l_{max}}$ via high-lift devices like flaps and slats. Flying high (lower density) increases stall speed (which is more dangerous).

Bonus material
As visible in the plot, $C_{l_{max}}$ depends on the Reynolds number and on the surface finishing. In particular if the the Reynolds number (i.e. speed) is smaller, $C_{l_{max}}$ becomes also smaller. A dirty wing is also going to have a lower $C_{l_{max}}$, 1.2 instead of 1.6 in our example. This implies that a jetliner in landing phase after having had a rough day is going to have a slightly lower $C_{l_{max}}$ i.e. higher stall speed.

That's a good explanation. Is this V-stall a TAS? Because stall IAS doesn't change with density; also, if it is TAS, I believe that the density in the denominator should be relative density and not absolute density.

@AdityaSharma V is airflow's speed as seen by the wing.

Just verified, the V here is the TAS. Also, the density here should be relative density (absolute density divided by ISA-MSL density). Thanks

@AdityaSharma ok

While this V is indeed TAS, the density is absolute (as written in your equation) and not relative (as earlier suggested by me); excuse me for that, my bad. (Also, I know it's wierd that I'm randomly coming back here after a month; nevermind, just wanted to correct my mistake...)

@AdityaSharma:

stalling occurs when a wing exceeds a critical Angle of Attack

That is the stock answer, the right answer, passes the written test.
But as a pilot, operating an aircraft, reading your POH, it says stall speed.

"references to "stall speed", apparently a speed below which a plane will stall"

How is this related to Angle of Attack, and why is stalling speed higher in a turn?
the real reason for stalling is that load force is more than the amount of lift force the wing can create under a given set of conditions.  The pilot exceeds the critical Angle of Attack by pulling the stick back too far in an effort to create adequate lift.
For any given aircraft, the given set of conditions are:
Lift = Load (Mass × G force) = Density × Wing Area × Coefficient × V$^2$
Defining "Stall speed" based on Load covers all bases of flight.

Stall is defined in terms of speed for many GA aircraft because other variables are more or less constant and Angle of Attack is at its lift producing maximum

In level flight, at 1 G, the stall speed is, for example: 50 knots (flaps up).
Here, we may ask what is the "coefficient of lift"?  This term is based on Angle of Attack and Airfoil type.  When you lower your flaps, airfoil type changes, enabling increased lift without increasing aircraft AoA$^1$ or airspeed$^2$.  Now, one can go slower before stalling, for example: stall speed 45 knots (flaps down).
Now for turns:  stall speed 60 degree turn.
Load factor is 2 G.  Coefficient of lift, density, and wing area are constant, velocity must be greater.  You can read it from your POH, or calculate it as: V$^2$ = 2 × 50$^2$

V stall = 1.41 × 50 knots or 71 knots

Now for cases where Load is less than 1  G as previously discussed in current answers.
Aside from aerobatics, and an Aviation Stack Exchange favourite:  lift is less than weight in a climb    , we have the emergency descent.  Yes, that's right, lift is also less than weight in a descent (as a mirror image of a climb) because now the drag component (rather than a thrust component) is helping resist gravity.  This means Angle of Attack will be less than that required for level flight.  Emergency descent turns are also performed at a higher airspeed, which additionally makes them safer.
$^1$ lowering flaps does increase local AoA at the wing.  This is one reason that flaps are placed next to the fuselage, effectively increasing the "washout" of the wing tips.  This ensures the warning buffet will start near the fuselage. The net effect is a lowering of stall speed (an increase in maximum lift for a given airspeed).
$^2$ drag also increases.  Throttle must be added to maintain airspeed (or aircraft must lower its pitch to the horizon).

That seems right; just wanted to point out, load is not weight × G-force. Weight itself is a force, and with G-force I suppose you mean normal acceleration. Load is mass × normal acceleration. Also on that note, this might seem unrelated, but how does climbing or descending affect the rate of turn for a given bank angle? Because apparently climb/descent reduces the load factor.

@AdityaSharma my guess is that because the required lift is less, the planes trim speed is reduced,  the rate of turn is less.  Also to be considered is the flight path, which is no longer a horizontal circle, but a helix.  Taken to extreme, the plane increasingly rolls about the point rather than pitching and yawing about it as in a level turn.  Good future question for ASE (I rarely dive or climb steeper than 10 degrees).

Thank you very much for the input; your statement sounds quite reasonable, although regarding trim speed, yes it'll reduce and that will have an effect, but let's assume it constant, because that was the case I'm interested in. Also worth noting is that it's the horizontal component of lift that provides the required centripetal force for a turn, and in our case, that lift has reduced. I still don't understand this fully, and if this has already not been answered, I'd love to ask this question myself. Good day!

@AdityaSharma neither do I, but thankfully it's not "the slower plane with the same lift has the greater rate of turn".  And the helix path is a greater distance to travel. From experience, any type of complex manuever is best done with excess speed.  We calculated 71 knots for a 60 degree turn stall (when 1 G stall was 50 knots), be we do them at 90 knots to be safe. But I will look forward to your next post, and good day also.

A stall disrupts the laminar flow of wind across the top wing surface, which is what's producing lift.
Because of that I have my doubts that it is ONLY dependent on AoA. In fact, I'm pretty sure you could induce a stall without changing the AoA at all using a turbulator on the leading edge (a la original KasperWing) to create eddies across the top of the wing.
Change my mind. :-)

Comments are not for extended discussion; this conversation has been moved to chat.

"A stall disrupts the laminar flow". Being the flow laminar is not necessary. Indeed if the boundary layer is turbolent it might even delay stall.

Oh sure, you could establish a tight boundary layer that was chaotic. But that would only establish the laminar flow above the boundary layer, right?
Also, a high speed stall doesn't involve the AoA only. In fact, it isn't the AoA that causes the stall. It's the rapid change of the AoA that triggers the turbulence over the top of the wing.
So, I am still not convinced that "only AoA" causes a stall. I think that's roughly correct but not quite precise.

I think the truth is a stall doesn't have to be triggered by a high angle of attack. It's the laminar air flow detachment that causes it. So anything that detaches the airflow can cause a stall.

Ralph, another comment has 5 replies. How come you moved mine to chat after only one reply?


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Actual non-axial airflow (sideslip) for a propeller driven aircraft
I am making a propeller model for a two-engine propeller driven aircraft (like a Dornier 228). I have expanded my model to include the non-axial airflow as well. $$ $$
By non axial airflow, I mean that the air does not strikes the forward moving aircraft straight along the propeller axis $v_x$, but in some angle. Imagine the propeller rotating along the $v_x$ axis in the figure below:

I want to generate the data from the model for some meaningful range of the sideslip angles ($\alpha ,\beta$). I could obviously choose a range [$-90^\circ 90^\circ$]. But the simulation time increases exponentially with such a large number of datapoints.
$$ $$
Generally, I think, for a propeller driven aircraft, it should not be that high. I was thinking to take a range of [$-15^\circ 15^\circ$]. $$ $$
Can anyone who has a bit of experience in these kind of aircraft, please suggest a practical range of the sideslip angles that is generally encountered.
Thanks a lot in advance :)

Are you simulating only the propeller, or also the engine and aircraft it will be mounted on?

I am simulating only the propeller


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Did the Concorde have flat plate airfoil?
Did the Concorde have flat plate airfoil?

this is because in all the images I have found it appears to be a flat plate

Simple images like that are not what you should be using to base an assumption off, but even in those images you can see it is not a flat plate.

Please provide additional details to highlight exactly what you need.

The Concorde, like many other supersonic aircrafts, had very thin airfoil mainly due to aerodynamic reasons. This answer gives a good overview on this topic.
Anyway the airfoil was definitely not flat i.e. neither a straight line nor without thickness. The following picture shows the central section of a Concorde and it can be seen that the airfoil there was quite thick:

Concorde central section, aft view (source)
Following one rib from the leading edge to the trailing edge, like the 33+51 in the next cutaway (source), one can more or less unterstand the airfoil shape:

Some reasons for the wing having a delta shape and not being flat can be found in this answer.


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At what point does a turboprop become more fuel efficient than a jet engine in large commercial aircraft?
Is there a formula that can be reliably used to determine when turboprops become the better option for domestic flights in a plane similar to a 737 in capacity and size? Also could this formula be applied to trans-continental/ trans-oceanic flights and larger planes? Should Southwest Airlines only be fling turboprops to save money or should every international airline be looking to switch at some point?

Related, if not an actual duplicate

What do you mean exactly with "when turboprops become better"? Do you have a speed in mind? Or a distance, or a weight or a time...?

Is there a formula that can be reliably used to determine when turboprops become the better option

A formula not but an indicative plot yes. The 5th slide of this presentation (slide that I repost here under and that has been taken from ¹), shows a comparison of the specific fuel consumption for several propulsion technologies:

As visibile, the fuel consumption of a typical modern turboprop overcomes the one of turbofan at some Mach 0.5 and that is the point where a turbofan becomes a better option.

¹ Daniel P. Raymer, Aircraft Design: A Conceptual Approach

This! This is the exact relevant plot! Thanks for that, although a bit dated, I think it shows exactly what the question asks for

@U_flow: I'm glad I could help

There isn't a one-fits-all formula. It would depend mostly on the distance between the city pairs you want to fly between. Turboprops have lower seat-mile costs, but are slower (the fastest one, the Q400, can do 360 kt true) and limited to the mid 20s flight levels. This means they can't get above much of the bad weather in the temperate latitudes. Jets just transition through icing conditions climbing or descending most of the time; turboprops may have to cruise in them.
For shorter distances, turboprops make sense, say up to 1000 miles (Q400 max range is about 1500), but people don't like to ride in them more than a couple hours, and for longer distances you need the ability to go above FL290 to get the high cruising speeds and get into the stratosphere to avoid the weather, and turboprops aren't certified to go that high, (and even if they could they would get in the way of jets on busy airways).
There's also passenger appeal. In the regional business, operators would use 50 and 70 seat jets to service 300-500 mile city pairs that would be more cheaply served by Dash 8s or ATRs, mostly because the passengers demanded jet service and were happy to pay a higher ticket price.
A Boeing 737 equivalent turboprop would be the Bristol Britannia 139 seat airliner, designed for transatlantic service in the late 50s, but it's service ceiling of 24000 ft and speed about the same as a Q400 meant it was a long haul across the Atlantic, through a lot of the weather, was quickly replaced by jets in transatlantic operations.


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Is it normal to hear only a tone when listening to a VOR?
I was using my RTL-SDR to listen to the VORTAC at Del Norte County Airport / Jack McNamara Field (KCEC) on 109 MHz. All I heard was a constant unmodulated carrier. Is that normal?

Were you listening in AM mode?

@tedder42 upper sideband set to 108.999 MHz, so the carrier was at 1 kHz in the audio output. Should I have been using AM?

definitely try AM. Airband is AM. I don't have a SDR set up to test though.


text:
Aside from primary radar, how did ATC monitor planes' locations before ADS-B?
From what I understand, air traffic controllers can monitor planes with radar, often called primary radar, or with ADS-B. I've seen ADS-B called "secondary radar," although it isn't really radar, but I've also seen the phrase "secondary radar" used referring to something that ADS-B replaced. I've also seen references to "SSR" (secondary surveillance radar? just a guess), which also appears to have been replaced by ADS-B.
My understanding:

Primary radar: "normal" radar, similar to what ships have; has been used for a long time and is still used
Secondary radar: originally "SSR"(?); SSR replaced by ADS-B

Is this correct?

https://en.wikipedia.org/wiki/Secondary_surveillance_radar

Does this answer your question? What is the difference between SSR and ADS-B? and see also How is radar separation assured between primary and secondary targets?

See also too How prevalent is traditional radar tracking of commercial aircraft? ...it seems like any one of the "related" posts that should have appeared when you typed this question would have answered it.


text:
When did the United States stop issuing pilot "licenses" (and start issuing "certificates")?
The first document issued by the US federal government authorizing a person to fly an aircraft was issued on April 6, 1927 by the Aeronautics Branch of the Department of Commerce, and it is called a license, not a certificate. When did the US stop issuing pilot "licenses" and start using the word "certificate"?

757toga said that his father's pilot "certificate" was issued September 29, 1946, and Amelia Earhart's "license" was issued in 1930, so the change almost certainly happened at some point between 1930 and 1946. (Earhart's license was last endorsed in 1935, but this doesn't prove that a new authorization issued between 1930 and 1935 wouldn't have been called a certificate.)

Do you have a reference for the first authorization? Who said it was called a "license" in the first instance?

@GregHewgill It's in the FAA Pilot's Handbook of Aeronautical Knowledge.

I trust the PHAK when it comes to Aeronautical Knowledge, but on a historical detail like this I could easily imagine the author using vernacular over a strict administrative definition in effect now, or at the time.  People today still often use the common term "license".  (and then there are those who correct them...)

@MichaelHall it says "license" on an image of the document, not just in the body text. I added a screenshot to the question.

That is really cool!  They should put photos on them again.  For years it was nothing but a nasty little piece of paper, at least the cards now are better than that...

Is this not merely semantics? The certificate merely indicates that the USG certifies a person to exercise certain privileges (i.e., license). In essence, the certificate is the physical proof that you have a license to do something.
The “license” above is really a certificate.

@Timbo there's no practical difference, but I'm interested in knowing when they changed the terminology.

What I mean is that there is no actual difference. A license is abstract. The certificate is a concrete object. The two go together. A certificate is the object to show that you have a license.

@Timbo at some point, they stopped using the word "license" entirely in formal usage. My question is asking when they made that change.

Ok, fair enough. In case you’re interested, the actual law that created the requirement used the word certificate. “f) Provide for the issuance and expiration, and for the suspension and revocation, of registration, aircraft, and airman certificates, and such other certificates as the Secretary of Commerce deems…” What is physically printed doesn’t change that it is a certificate (hence, why the Dept of Commerce ‘certifies’ in the picture above).

1937.
It took some digging but there is a U.S. CAR from November 1937 with the following regulation.

20.3-PILOT COMPETENCY CERTIFICATE.

20.30-Provision for Issuance.
An appropriate pilot certificate of competency will be issued by the Secretary to a natural person who is an applicant therefore, after approval of an application made and proofs submitted in connection therewith and if upon inspection and examination such applicant is found by the Secretary. to meet the appropriate minimum requirement prescribed in CAR 20.1. Holders of valid pilot licenses, except student licenses, may pilot aircraft pursuant to such authority until the expiration thereof. Holders of valid student pilot licenses may pilot aircraft pursuant to such authority until the expiration thereof or for 6 months after the effective date of these regulations, whichever is the shorter period. Upon the expiration of each pilot license as just set forth the holder, upon meeting the requirements for the renewal or re-issuance thereof and for any ratings held, may have issued to him the following certificates and ratings:

(a) If the holder of a student license, a solo certificate...
(b) If the holder of an amateur license, a solo certificate...
(c) If the holder of a private, limited-commercial or transport license, a private, limited commercial or commercial certificate respectively...

It would make sense to make the change at the end of 1937 when the Aeronautics Branch of the Department of Commerce became the Civil Aeronautics Administration (CAA) in 1938 per the Pilot's Handbook of Aeronautical Knowledge.

If you look up the definition of certificate and license, you will see the license is what gives you the right to operate aircraft as per the limitations, and a certificate is the document which proves you got the license. Two different concepts. "License: a permit from an authority to own or use something, do a particular thing, or carry on a trade (especially in alcoholic beverages)." and "Certificate: an official document attesting a certain fact."
Proof of this is that if you lose the certificate (the card), you don't lose your pilot's license, they just issue you another card.

This is not true in the US. There is currently no such thing as a US pilot "license"; the term "certificate" is applied both to the document and the permission which it represents. Dictionary definitions are not necessarily legal definitions. There is such a thing as an FAA license, but it is only for spacecraft operators. https://www.ecfr.gov/search?search%5Bdate%5D=current&search%5Bhierarchy%5D%5Btitle%5D=14&search%5Bquery%5D=license&view=standard

@Someone, you are perhaps putting too much emphasis on the words and not what is being explained. The certificate is the proof that you have the license. That’s why the terms are nearly interchangeable. Even the FAA uses these interchangeably. https://www.faa.gov/faq/what-are-differences-types-pilot-licenses-certificates#:~:text=A%20private%20pilot%20certificate%20lets,by%20some%20air%20transport%20operations.

@Timbo they use the word "license" informally, but they do not use it in the regulations. I'm focusing on the words because my question is about the words. A certificate does not prove that you have a license; the regulations require that you have a certificate in order to operate an aircraft.

@Someone No. This is exactly how it works in the US. You earn your license and are given a certificate as proof of it. You are welcome to talk to your local FSDO if you have any doubts about that.


text:
Is there a general rule for picking a set heading point?
I'm currently working on a couple of Nav-logs. I have a leg where I have to climb from sea level to 9500'. This takes up about 26NM of horizontal distance. Is it bad practice or even wrong to pick a set heading point that far away?
I am able to visually navigate to this set heading point by following a highway and a creek which leads directly to it.

Can you clarify? Are you saying you'll be climbing, but in a straight line for 26NM? If there isn't any terrain considerations, there isn't anything wrong with that.  Maybe I'm not understanding the phrase "set heading point."

@Canuk There won't be any terrain obstructions. The set heading points on my Nav-logs are basically checkpoints points on my route where i would turn to a different heading. And yes in a straight line after departure for 26NM

It sounds like the exercise you are doing is to navigate to an initial top of climb waypoint by pilotage (also known as IFR = I Follow Roads), then starting a dead reckoning leg from the top of climb waypoint where a heading is selected based on wind drift calculations.
The distance to the initial waypoint is not important and it's logical to locate it at the top of climb, and being a long climb it's some distance away from your departure airport.
So whatever floats your boat is fine as long as you know where you are and where you're going, there isn't really a protocol to follow other than the logic of setting a waypoint at the top of the climb, and you can navigate by pilotage the entire trip if you feel like it (what I normally do - well, actually I just use my phone most of the time to get around these days).

If I was doing a PPL flight test and during the ground portion the DPE sees that I have selected the top of climb as my set heading point It would be acceptable as long as I can justify it by telling him that i can get to it by pilotage?

I would say so, but I can't read the mind of the DPE and perhaps the DPE wants you to dead reckon right from the airport for the purpose of skills evaluation. What does your instructor say about all this?

I'll ask him about this later today, but when I was first taught dead reckoning, paraphrasing his words: "You visually navigate to your first set heading point, go in straight lines as much as possible, and then you visually navigate to your destination passing your last set heading point".

I've asked my instructor. It is acceptable for the flight test. As long as I am able to justify the use of the top of climb as the set heading point and I can reliably visually navigate to that point, its ok.


text:
PTCHY LGT MOD SEV coverage on WX charts?
On GFAs, TAFs, METARs we see PTCHY LGT TURB, MOD TURB, -RA, +RA, etc. I was wondering where could I find the technical definition of these terms? For example the percentage coverage of these weather phenomena or the sky coverage in terms of oktas?

Check NOAA's FMH-1 and see if that answers your question; if not I'll try to put together an answer later.

Please be sure to mark the below answer as „accepted“, if you feel it has answered your question.

For the METAR codes you mentioned (compare United States of America Aeronautical Contractions, Section 1: Decode):

abbrev.
term

PTCHY
patchy

MOD
moderate

TURB
turbulence

RA
rain

LGT
light

The conditions for Light Rain are defined in the Federal Meteorological Handbook-1.
The conditions for Light/Moderate Turbulence is defined by the ICAO (I could only find the SkyBrary definition, not the original source in the ICAO documents).
The conditions for Patchy ("covers 25% or less") are defined by the FAA, eg. in 7930.2 Notices to Air Missions (NOTAM).


text:
Question regarding CAR 604.38
604.38 (1) No person shall conduct a take-off in an aircraft operated by a private operator unless an operational flight data sheet has been prepared and contains the following information:
(a) the date of the flight;
(b) the aircraft’s nationality mark and registration mark;
(c) the name of the pilot-in-command;
(d) the departure aerodrome;
(e) the destination aerodrome;
(f) the alternate aerodrome, if any;
(g) the estimated flight time;
(h) the fuel endurance;
(i) the weight of the fuel on board the aircraft;
(j) the zero fuel weight of the aircraft;
(k) the take-off weight and centre of gravity of the aircraft;
(l) the number of persons on board the aircraft;
(m) the proposed time of departure; and
(n) the estimated time of arrival.
(2) The pilot-in-command of an aircraft referred to in subsection (1) shall, on the completion of each flight, record on the operational flight data sheet the flight time, time of departure, time of arrival and aerodrome of arrival.
(3) The private operator shall retain a copy of the operational flight data sheet for at least 180 days after the day on which the flight is completed.
Does this mean If I owned an airplane I cannot fly VFR without a "flight plan"? Since almost all the above items are on the ICAO flight plan.

If you look at 604.02, it list the airplanes that the Private Operator requirement applies to:
Large Aeroplanes
Turbine Powered Aircraft
Pressurized Aircraft
Multi-engine Aircraft.
If it's for your own airplane not covered by the applicability, that Private Operator stuff doesn't apply.  As a regular non-complex airplane owner, you are supposed to file either a Flight Plan with certain information (not all that stuff in the list in your post) or a Flight Itinerary with a "responsible person", with the same sort of information, if you want to fly more than 25 miles from base.
When I go flying I just email a chum, a reasonably responsible one, or the missus, with the flight itinerary data for my plane, my general route and time expected to return. It's all just to make sure there is someone to call Air Rescue if you don't show up at the time you specify.


text:
Can short term escalation be applied exceeding life limit on Form 8130-3?
I have a case where there is maintenance item to replace a component when it reaches its life limit. This component life limit is stated on Form 8130-3 of said component referring to component manual. However, maintenance item above is not mentioned as AWL or CMR in aircraft TCDS.
From my understanding, FAA states that short term escalation should not be applied on maintenance item pertaining life limits specified in TCDS. Therefore, for maintenance item above, it is allowed to apply short term escalation (i.e. to postpone component replacement to later date). However, if I do that, the component would exceed life limit on Form 8130-3. Is it allowed to apply short term escalation based on that situation?

The FAA regional offices have a lot of autonomy and some are stricter than others on regulatory interpretation.  So on those sorts of questions, you might get different answers from different FAA regions.  That's probably something best asked of your local PMI because that's who'll you'll have to answer to in the end.

The limitations imposed by OpSpec D076 and the certificate holder’s procedures should not allow a short-term escalation that would compromise the airworthiness of an aircraft or any safety of flight issue. Unanticipated situations arise, such as contractor scheduling, conflicts in weather, parts availability, or other unscheduled maintenance; during which the short-term escalation of a maintenance interval may be used  What is the purpose behind requesting the escalation?


text:
How would you know if there was an AD issued for an aircraft?
How would I know if an AD was issued?
Is this information only given to owners of the aircraft? Or must you sign up with the FAA or Manufacturing company to get emails about that sort of thing?


text:
What is the purpose of warning areas?
What purpose does the warning area serve?
Is it like CFA'S, MOA'S?

Could you provide a little more detail, what is an example of a warning area you're asking about? What specifically do you want to know? What juristiction are you asking about?

Have you looked up the definition?  The purpose is often embedded in the definition.  (I.e. “international airspace with a high volume of military training…”

I had the definition but I wanted more of a vivid picture on what happens in that airspace.

AIM 3-4-4 states.

A warning area is airspace of defined dimensions, extending from three nautical miles outward from the coast of the U.S., that contains activity that may be hazardous to nonparticipating aircraft. The purpose of such warning areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both.

These areas have typically been used for hazardous activities e.g. supersonic flight by military aircraft, live firing of guided missiles (W-151 areas off the coast of Tyndal AFB), aerial warfare exercises, etc.
A chief difference between Warning and Restricted or Prohibited areas is that most Warning areas lie off the coast in international waters where the US does not have the ability to exercise control of this airspace or prohibit entrance under international law.  IFR traffic is routed around by ATC from these areas but there are no restrictions for VFR traffic entering Warning areas.  These The areas function sort of a courtesy call to both civil and military air traffic operating in international waters that the US conduct these kinds of hazardous activities within.

A key difference between Warning areas and Restricted areas are that the Warning areas are mostly in international airspace (over international waters) where no state is allowed to restrict access according to ICAO agreements. Operationally, ATC won't route any traffic through a Warning area, but they can't stop VFR traffic from entering (they will advise to avoid an active Warning area.) The areas off Eglin AFB are active most weekdays.


text:
Do pilots ever talk directly to each other over radio?
Do pilots ever talk directly to other pilots over air band radio, or only to air traffic control?

Informally, pilots talk to each other quite often, even on frequencies they're not supposed to (link is to a YouTube video of Kennedy Steve inviting pilots to heap verbal abuse on a pilot who hot-mic'd his preflight on JFK_GND).
Formally, aircraft have specific frequencies for air-to-air communications.

communications between private, fixed-wing aircraft, there is just one authorized frequency: 122.75 MHz. For general aviation helicopters: 123.025 MHz. Gliders and hot air balloons share 123.3 and 123.5 MHz.

122.9 has been used historically, and 123.45 gets mis-used so often it's called "Fingers" because its frequency's digits are in natural counting order.
Finally, when outside of controlled airspace, Common Traffic Advisory Frequencies (CTAF) are how aircraft coordinates with each other in regards to operations in airfields and other landmarks.

Thank you! So there's no legal way for e.g. a pilot of a GA airplane to talk to the pilot of a GA helicopter, other than by using an alternative radio service?

@Someone If they're in controlled airspace, they shouldn't need to. ATC is either separating them, or they're in VMC, operating VFR, and shouldn't need radio to see and avoid each other. Outside of controlled airspace, that's what CTAF is for (edited to include).

@Someone, what makes you think it is illegal to talk to another pilot?

@MichaelHall Strictly speaking, 47 CFR 87.185 (a) states that "Aircraft stations must limit their communications to the necessities of safe, efficient, and economic operation of aircraft and the protection of life and property in the air, except as otherwise specifically provided in this part". And nowhere in that part do they allow for casual conversation.

OK, but because there are two designated air-to-air frequencies, (one for fixed wing, one for helos) you are presuming that it is "illegal" for a fixed wing pilot to ever communicate with a helicopter pilot?  That seems like a very oppressive interpretation, and one that doesn't mesh with safe or efficient interoperations.  If I was briefing with a helicopter pilot for any reason I'd pick one of those freqs and not think twice about somebody questioning me.  Two frequencies are provided to spread things out, not to prevent or render illegal any cross-talk between category/class aircraft.

@MichaelHall the phrasing of the quote implies that. It didn't make sense to me either, but since I'm not a pilot and not very familiar with aviation radio protocol, I just figured I was missing something.

Also military pilots are in direct communication with eachother during operations for obvious reasons.  (The OP didn't specify just commercial or GA.)

Yes. They may talk directly:

on the designated en-route air to air frequencies. These are not linked to a specific location.

when relaying communications for ATC on ATC frequencies or for FSS on an FSS frequency, if a plane has a weak radio, is out of range[ie over ocean], or in a mountain valley.

on CTAF and unicom(sometimes the same frequency), which are most commonly linked to pilot-controlled airports but can be designated for other high traffic areas(the later is more common in Alaska). The airspace may be class E(controlled by ARTCC or TRACON/approach) or class G(uncontrolled).

on multicom. Multicoms are often used for special events, emergency operations like search and rescue or firefighting, fish and game management, etc..

on the emergency frequency 121.5 for any assistance needed.

You can ask atc for permission to speak with another on the freq, at least that happened when another pilot wanted to speak to me and asked and recieved permission.

FYI, you don't need permission to speak from ATC if the transmission is operationally necessary.  I have heard plenty of pilots jump in to relay a message to an aircraft that isn't responding for some reason after several attempts by ATC.   (e.g. "N123Y, Center is trying to call, they want you to switch to 124.75.")  ATC generally thanks them for helping.

And along those lines, ATC will sometimes ask you to contact the aircraft not responding.  But then you probably knew that already.  I was referring to a different situation where one pilot simply wants to speak with another on the frequency.


text:
How fast can a Cessna 172 taco?
What is the highest speed at which a Cessna 172 can taxi without lifting off the ground? If you removed the wings, how fast could it taxi? (Answers only answering the first part are fine; I doubt the published specifications include "maximum wingless taxi speed")

please don't change the headline ("How fast can a Cessna 172 taco?")

I'm just happy this isn't about the speed at which at 172's wings turn into a taco

The Cessna 172 has an NACA 2412 airfoil with 1 1/2 degree of wing incidence at the root with 3 degrees of negative washout at the wing tips.
According to the Airfoil Tools data charts, this will generate a lift coefficient of around 0.4, compared with 1.6 at stall.
If the "stall speed" is around 50 knots at maximum coefficient of lift, then the Lift Equation can be used to determine the speed required to fly with 1/4 the coefficient of lift:

50$^2$ × 1.6 = X$^2$ × 0.4

X = around 100 knots
So, theoretically, it could be done, but it would be very tough on the nose wheel and is not recommended.  Key here would be the trim setting, which controls the elevator.  If it were set for "take off", then that is what will happen (even without yanking the stick back) at around 65 knots.
On a brighter note, it does encourage one not to slam on the brakes after nosewheel touchdown when landing for fear of being lifted back into the air from a slight headwind gust. Have a nice taxi back to your parking spot.

Generally, trim setting is reduced significantly during transition to cruise airspeeds.


text:
Why did the British Royal Air force not see a mass adoption of American Fighter planes and bombers?
I understand the RAF made extensive use of C-47 and other support aircraft from the US, but they never seemed to adopt fighters and bombers for frontline service like the British Army so eagerly did with the m3, lee and sherman and other equipment. What was the reason for this? Where there not enough British pilots available to justify the purchase? Or was British manufacturing just better suited to producing airframes than tank hulls?

Not sure where you get your information, but the RAF extensively used P-51 Mustangs (it was designed for them originally), P-47 Thunderbolts (in the Far East and Middle East), P-40 Tomahawks (in the Far East and Middle East), and B-25 Mitchells (Europe, Middle East and Far East) throughout the war.
They ordered some P-38 Lightnings early on but specified non-counterrototating engines and no supercharging, and the performance was disappointing as you would expect, and further orders were declined.
The RAF also operated B-17s and B-24s and PBYs in Coastal Command. The Royal Navy operated Corsairs and Wildcats off carriers. It was the Royal Navy that convinced the US Navy to revisit carrier operations for the Corsair, after the Navy initially abandoned carrier ops and transferred their Corsairs to the Marine Corps for land based ops, by perfecting the curved approach path on Royal Navy carriers.
The main limitation would be available quantities restricted as the US started to prioritize its own needs
Meanwhile, the US Army operated DeHavilland Mosquitos for reconnaissance and pathfinding, as well as Spitfires.
I'm sure there are other types I missed.
My father flew C-47s in Burma, and was based at RAF Tulihal just inside India, and the base included RAF squadrons of both B-25s and P-47s that provided tactical support to the 14th Army's drive down the Irrawaddy valley to Mandalay. When I was little he told me stories of orbiting near Japanese lines in their Dakotas and watching the RAF Mitchells and Thunderbolts pound Japanese positions so they could make their drops over British Army positions.

My conjecture is that since US manufacturing is closer to the Far East theatre than UK manufacturing, but UK manufacturing was (obviously much) closer to the European theatre, the RAF would have primarily used UK planes in Europe and US planes in the Far East. Which since many British history buffs are more interested in the European Theatre gives the impression that the RAF flew mainly UK types.

Mainly it was that the Far East was a secondary priority, way lower priority as far as  Britain was concerned, and had to distribute their more limited resources a bit more carefully.  Plus the only major theatre of operations for UK was India/Burma. The RAF did send Spits to Burma in 1943 and 1944, Mark Eights I believe. The Spit could fly circles around an Oscar (Army Zero). The UK just couldn't produce enough airplanes in-house, so they supplemented their needs with US types, and in some cases like the B-24, and B-25, they were just the best design for the job.


text:
Can someone be an ATPL holder while having Pineal Cyst?
Does anyone know if I can become an ATPL holder with pineal cyst (2cm).I have no symptoms and was discovered accidentally because as a family we do MRI every 5 years (It is nothing it is just a family custom?I suppose)I have asked medical experts and I dont know some say yes and some say no...
17 years old
Europe-->EASA

Sounds like you’ve asked everyone but the aviation medical examiner who is the one who can actually answer it.

You can check the EASA easy access rules for medical requirements for conditions that are immediately disqualifying. I'm not sure what your condition falls under but in all likeliness it requires "further assessment". This can mean anything from a letter from your doctor, consultation with your country's transport authority, to additional medical evaluations.
Getting your first medical is not cheap but not compared to the cost of learning to fly, it's not that bad. By getting ahead of things now, you not only buy some peace of mind but also show prospective employers that you are serious about flying.


text:
does ice accumulation of wing affect its flutter speed
I am trying to find a possible link between wing icing and flutter.
I want to know if ice accretion mass will change aeroelastic properties of the wing.
Does wing icing affect the flutter speed of wing? Will ice accretion cause early onset of flutter?

The amount of ice needed to affect "aeroelastic properties" would already be drastically affecting lifting properties.

I agree with Robert. By the time enough ice were to accumulate to affect the wing's structural properties, you won't be flying anymore.


text:
How many channels does the VOR have?
VORs are assigned radio channels between 108.0 MHz and 117.95 MHz. How many channels are in-between? I guess that each decimal value represents 1 channel? for instance (108.1)(108.2)(108.3)(108.4)......(117.94)(117.95).
Sorry If my question looks dumb, I'm not professional but student.

VORs are assigned frequencies with 50kHz (or 0.05MHz spacing, if you prefer). Thus, there are 200 possible frequencies.
(In the US, 40 of those frequencies are reserved for ILS, so the total number of available VOR frequencies in the US is 160.)

From Wikipedia:

VORs are assigned radio channels between 108.0 MHz and 117.95 MHz (with 50 kHz spacing);

This means the lowest channel is 108.0MHz, the next one up is 108.05MHz, and so on.
This gives (117.95-108.8)/0.05 + 1 channels, or 200.


text:
What is the working principle of a dorsal fin?
In simple words could someone please explain the working principle of a dorsal fin in a two engined propelled airplane?

Dorsal Fin
It is vertical surface located above the fuselage; it has a low aspect ratio and (usually) a high sweep angle. Such aerofoils inherently have a high induced downwash, which delays their critical AoA to a higher angle. This means that the dorsal fin will stall at higher sideslip angles.

If an engine failure occurs on a twin-engine aircraft at low airspeeds, the resulting yawing moment can produce large sideslip angles. If the fin stalls under this condition, the aircraft will lose directional stability, and the yawing moment of the live engine will force the aircraft to spin out of control. This is certainly not ideal, and the dorsal fin delays this occurance to a higher slip angle.
At large sideslip angles, the dorsal fin also sheds a strong vortex across the main fin surface (including the rudder). This re-energies the boundary layer, thereby delaying seperation. Not only does this increase the stall angle of the main fin, but it also increases the effectiveness of the rudder - improving its ability to counteract the yaw. This makes the dorsal fin sutable for twin-engine aircraft.